Direct lighting luminaire



June 13, 1939. L, DOANE 2,162,330

DIRECT LIGHTING LUMINAIRE Original Filed May 29, 1936 INVENTOR LEROY C. Dad/7e.

ATTORNEY Patented June 13, 1939 PATENT OFFICE 2,162,330 DIRECT LIGHTING LUMINAIRE .Leroy C. Doane, Meriden, Conn., assignor to The Miller Company, Meriden, Conn, a corporation of Connecticut Application May 29,

1936, Serial No. 82,497

Renewed March 12, 1938 I v 4 Claims.

The present invention relates to direct lighting luminaires and is more particularly directed to such lurninaires employing long vertically disposed light sources.

It has been customary in direct lighting units having concentrated light sources, to provide reflectors generally of annular configuration about the light source for redirecting the light into the desired direction. With the reflector and concentrated light source, it is possible to obtain a satisfactory more or less cut-off of direct light so as to shield the light source from the direct line of view.

It has been found impractical to extend the length of the reflector when used with long light sources to protect the sources against direct observation, and the present invention contemplates a luminaire wherein the ordinary form of sheet metal or other reflector (commonly used with concentrated filament lamps) may be used with long light sources, and the angle of emission of direct light controlled by means of a diffusing ring placed in such a position as to confine the direct light to suitably lowered angles as to be out of the ordinary line of vision.

The accompanying drawing shows one embodiment in which the invention may take form, it being understood that the drawing is illustrative of the invention rather than limiting the same.

In the drawing,

Fig. 1 is a vertical sectional view through a lighting fixture;

Fig. 2 illustrates the photometric curve for such a fixture as well as indicating the fixture in outline; and

Fig. 3 illustrates a modification in which incandescent lamp bulbs are used in addition to the long light sources.

The long light source is in the form of an elongated bulb Ill, which preferably forms part of a high intensity mercury vapor lamp, whose electrodes are diagrammaticallyillustrated at H and I2. The reflector R. is of conventional out- 45 line, and has a lower, comparatively deep, skirt portion I3, an upper, comparatively flat, portion l4, and a substantially cylindrical supporting shell l5. The reflector supports three downwardly extending vertical members l6, preferably in the form of rods. They are secured in place by locking lugs I1 and nuts I8. The lower ends of these members are'hook-shaped and bent upwardly as indicated at l9, and receive an annular cylinder or ring 20 of diffusing glass.

Where desired, the lurninaire may be provided with auxiliary incandescent lamps, such as indicated at 2| in Fig. 3.

Typical light rays from the upper part of the light source strike the walls of the reflector and are reflected downwardly. The paths of such rays are indicated at 25 and 26. Some of the light from the lower part of the source is emitted above the ring 29 and reflected downwardly as indicated by the rays 27 and 28. These rays build up a comparatively intense illumination directly underneath the lighting unit, as indicated by the lower part of the photometric curve of Fig. 2.

Some direct light from the upper part of the source passes out through the mouth of the re,- flector, as indicated by the ray 29. The line 3|], drawn from the bottom of the reflector R. across the top of the ring 20, is at about 67 to 70 to the vertical, and this indicates the direct light cut-off for light coming from the upper part of the source.

The line 3|, located by the lower edge of the dilfusing ring 20, and the bright lower electrode of the lamp bulb, shows the line of direct light cut-off from the bottom of the light source. The lines 3|] and 3| are approximately parallel.

If the ring 20 were not present, the line of direct light cut-off would be that indicated by the line 32 on the drawing, which is about 10 higher than the lines 30 or 3|, so that the zone between the lines 32 and 3| of about 10 to 12 extent, receives diffused lighting only. The corresponding reference characters are used in Fig. 2 to indicate the angle of difiused light cut-01f and the angle of direct light cut-off.

The upper part of the ring 20 is so placed that the line of direct cut-off from the upper part of the source is controlled. The upper part of the ring also functions to prevent direct light from the lower part of the source falling on the lower part of the skirt of the reflector and forming bright images by reflection.

The path of rays which might produce such bright images is indicated by the dotted rays 33 and 34.

It will be noted from the drawing that the reflector is slightly deeper than the length of the lamp bulb so that the bulb does not project beyond the reflector, also that the ring is housed within the reflector so as to be protected by the reflector. The glass ring is readily removable whenever desired. It is supported in a secure manner, and prevented from rattling by the spring hooks which receive it. The ring supports also afford a considerable protection for the lower part of the lamp bulb, and yet do not interfere in any way with access to the bulb for replacing purposes nor with the cooling of the bulb.

It is apparent, within the scope of the invention, modifications and different arrangements may be made other than that herein disclosed, and the present disclosure is illustrative merely, the invention comprehending all variations thereof.

What is claimed is:

1. A luminaire comprising a downwardly opening annular reflector having a normally vertical axis, an axially disposed long light source extending from the top of the reflector nearly to the plane of the bottom opening, a short light diffusing ring about the lower end of the source, the lower edge of the ring being positioned in relation to the lower terminal of the source so as to out oiT direct light at a predetermined angle below the horizontal and permit the escape of a wide cone of direct light downwardly there through, the length of the ring being sufficient to extend to a height to intercept upwardly slanting lines drawn from the lower edge of the reflector parallel with the line of cut off of the lower edge of the ring but insufiicient to screen the reflector from direct light from the upper part of the source, whereby the direct light emitted from the source above the ring and passing between the mouth of the reflector and the top of the ring is more nearly vertical than the most widely divergent light in the cone of direct light emitted below the ring, and a plurality of reflector carried members to which the ring is detachably secured.

2. A luminaire such as claimed in claim 1, wherein the said members extend vertically downward from the top of the reflector.

3. A luminaire such as claimed in claim 1, wherein the said members extend vertically downward from the top of the reflector and their lower ends are upturned for slip engagement with the ring.

4. A luminaire comprising an annular downwardly opening reflector, an axially disposed long light source extending from the top of the reflector nearly to the bottom, a diffusing ring about the lower end of the light source, the lower edge of said ring being so positioned in relation to the light source that the angle of cut-off of direct light from the bottom of the source is determined thereby and its upper edge lying in a line drawn from the lower edge of the reflector toward a point on the light source and substantially parallel to a line drawn from the lower terminal of the light source and through the lower edge of the ring, the ring establishing a zone of difiused light between the upper and lower zones of direct light, and a plurality of reflector carried members to which the ring is detachably secured.

LEROY C. DOAN'E. 

